PURPOSE: This study was conducted to examine the effect of a Happiness Self-Coaching program for new graduate nurses working in cancer care units. METHODS: A quasi-experimental pretest-posttest, nonequivalent control-group design was applied to conduct the study. Study participants were new graduate nurses employed within 12 months and working as shift employees at G university hospital, located in J city. A total of 21 new graduate nurses participated in the study, 10 in the experimental group, and 11 in the control group. The happiness self-coaching program was conducted weekly for 70 minutes from February 1 to June 6, 2016 for 6 weeks. The experimental group received the Happiness Self-Coaching program through lectures, presentation, group activities, and strength card play. Data were analyzed by using repeated measure ANOVA and paired t-test. RESULTS: The experimental group demonstrated significantly higher happiness (F=6.82, p=.003) and self-efficacy (F=3.38 p=.045) levels compared to the control group.